Water-soluble copolymers based on olefinic sulfonic acids, method for the production thereof and use of the same

ABSTRACT

Water-soluble copolymers based on olefinic sulfonic acids, olefinic dicarboxylic acids, vinyl amides and vinyl ethers and/or allyl ethers and/or bisacryl derivatives are described as well as processes for their production and the use of these copolymers as water retention agents, thickeners or anti-segregation agents for aqueous building material systems that contain hydraulic binding agents such as cement, lime, gypsum, anhydrite etc. or for clay suspensions preferably based on bentonite.

The present invention concerns water-soluble copolymers based onolefinic sulfonic acids, olefinic dicarboxylic acids, vinylamides andvinyl and/or allyl ethers which can be used as water retention agents,thickeners or anti-segregation agents in plaster and cement mortars thatare for example used in the form of plasters, and in clay suspensions.

Cement and plaster mortars are used in the building industry to bondvarious ceramic materials and surface coverings to the substrate or tocover surfaces (plaster). In this process the tempering water must beprevented from being removed from the mortar by capillary forces ofporous substrates. This is achieved by adding water retention agents.These can either bind water per se due to their chemical structure (e.g.by means of hydrogen bonds) or they result in the formation of animpermeable filter cake of the mortar on the substrate. Thus for examplemixtures of clay and guar are described as water retention agents inEP-A 1 090 889. The documents DE 195 43 304 A1 and U.S. Pat. No.5,372,642 disclose cellulose derivatives as water retention agents.

Furthermore setting agents are often added to mortars to prevent themortar from flowing out of cracks to be repaired or from verticalsurfaces. This is often achieved by adding cellulose and/or starchderivatives. Thus setting agents which contain at least one celluloseether and one starch ether are disclosed in EP-A 773 198. According toEP-A 0 445 653 and DE 195 34 719 A1 setting agents are described whichcontain the clay mineral hectorite in addition to cellulose derivatives.Thickener systems are known from EP-A 0 630 871 which contain at leastone ionic or non-ionic surfactant in addition to a cellulose ether.

Suspensions of swellable clays are used in foundation and soilengineering to produce earth-supporting liquids for excavations.Examples of this are the construction of diaphragm walls, and thesinking of shafts, wells and caissons (see also: F. Weiss, “DieStandfestigkeit flüssigkeitsgestützter Erdwände” in “Bauingenieurpraxis”70 (1967)).

The cellulose derivatives used according to the prior art have thedisadvantage that they delay the stiffening of cement mortar. However,this is undesirable in many cases since a relatively rapid stiffening ofthe mortar is better for subsequent treatment. For this reason it isoften necessary to additionally add accelerators to cement slurrieswhich, however, is not unproblematic in practice due to the necessity ofan exact dosage.

Hence the object of the present invention was to provide water-solublecopolymers which do not have the said disadvantages of the prior art,but can be produced in a technically simple manner and give thecorresponding building material systems good application properties inthe working and hardened state.

This object was achieved by the copolymers according to claim 1.

It has surprisingly turned out that the water-soluble copolymersaccording to the invention can be used as water retention agents,thickeners or anti-segregation agents without prolonging the setting andstiffening times.

The copolymers according to the present invention consist of at leastfour structural units a), b), c) and d). The first-structural unit a) isderived from olefinic sulfonic acids of formula (Ia) and/or (Ib):

in which

-   R¹=hydrogen or C₁-C₅ alkyl,-   R²=C₁-C₂₀ alkylene, carboxy-C₁-C₂₀-alkylene,    carboamido-C₁-C₂₀-alkylene or phenylene-   M=hydrogen, ammonium or a monovalent, divalent or trivalent metal    cation and-   x=1 to 3.

Alkali ions and in particular sodium and potassium ions are preferablyused as monovalent metal cations; alkaline earth ions and in particularcalcium and magnesium ions are preferably used as divalent metal cationsand aluminium or iron ions are preferably used as trivalent cations.According to a preferred embodiment R¹=hydrogen andR²=—CO—NH—C(CH₃)₂—CH₂— in formula (Ia).

The structural unit a) is derived from monomers such as2-acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid,vinylsulfonic acid and methallylsulfonic acid and salts thereof.2-Acrylamido-2-methylpropanesulfonic acid and salts thereof areparticularly preferred.

The second structural unit b) corresponds to formula (IIa) and/or (IIb):

in which

-   R³ and R⁴=—COO⁻(M^(x+))_(1/x) or are together-   R⁵=—COO⁻(M^(x+))_(1/x)-   M=hydrogen, ammonium or a monovalent, divalent or trivalent metal    cation and-   x=1 to 3.

Again alkali cations (Na, K) are preferred as monovalent metal cations,alkaline earth cations (Ca, Mg) are preferred as divalent metal cationsand aluminium and iron ions are preferred as trivalent metal cations.

Maleic acid and salts thereof as well as maleic anhydride and alsofumaric acid, itaconic acid or salts thereof are suitable as monomerswhich form the structure(s) (IIa) and/or (IIb).

The third structural unit c) corresponds to formula (III).

in which

-   R⁶=hydrogen or C₁-C₅ alkyl-   R⁷ and R⁸=hydrogen, C₁-C₁₀ alkyl or are together —(CH₂)_(y)— and-   y=3 to 7, in particular 3 to 5.

N-vinylcaprolactam, N-vinylpyrrolidone and also N-vinylformamide,N-vinylacetamide and N-methyl-N-vinylacetamide are preferably used asmonomers that can form the structural unit c).

The fourth structural unit d) corresponds to formula (IVa) and/or (IVb)and/or (IVc):

in which

-   R⁹=hydrogen or C₁-C₅ alkyl-   R¹⁰=C₁-C₁₀ alkyl, C₁-C₁₀ aminoalkyl, C₁-C₂₀ hydroxyalkyl, C₁-C₄    alkyl or hydroxyl-terminated mono- or poly-C₂-C₃-alkyleneoxy    (containing 1 to 400 alkyleneoxy units), C₇-C₂₀ alkylaryl, C₇-C₂₀    hydroxyalkylaryl, C₆-C₁₀ aryl, C₆-C₁₀ hydroxyaryl-   R¹¹, R¹² and R¹³=hydrogen or C₁-C₅ alkyl and-   R¹⁴=hydrogen, C₁-C₂₀ alkyl, C₁-C₁₀ aminoalkyl, C₁-C₂₀ hydroxyalkyl,    C₁-C₄ alkyl or hydroxyl-terminated mono- or poly-C₂-C₃-alkyleneoxy    (containing 1 to 400 alkyleneoxy units), C₇-C₂₀ alkylaryl, C₇-C₂₀    hydroxyalkylaryl, C₆-C₁₀ aryl, C₆-C₁₀ hydroxyaryl or C₁-C₂₀    alkylenesulfonic acids optionally substituted with hydroxyl group(s)    e.g. with 1 to 3 hydroxyl groups, and ammonium, alkali or alkaline    earth salts thereof-   X=O, NH-   n=1 to 6-   r, s=0 to 5-   t=1 or 2-   u=1 to 50 and-   R⁶ has the above-mentioned meaning.

According to a preferred embodiment the C₁-C₂₀ hydroxyalkyl, C₇-C₂₀hydroxyalkylaryl and C₆-C₁₀ hydroxylaryl residues for R¹⁰ and R⁴ informulae (IVa) and/or (IVb) have one or more e.g. 2 to 5 and inparticular 2 to 3 hydroxyl groups.

Furthermore in formula (IVa), R⁹ preferably represents hydrogen and R¹⁰represents a C₁-C₁₆ hydroxyalkyl or a methyl- or hydroxyl-terminatedmono- or poly-C₂-C₃ alkyleneoxy residue.

Finally R¹¹, R¹² and R¹³ in formula (IVb) preferably denote hydrogen andR¹⁴ preferably denotes 2,3-dihydroxypropyl, 3-hydroxypropyl or2-hydroxypropyl-3-sulfonic acid and ammonium, alkali and alkaline earthsalts thereof.

The monomers which form the structural unit (IVa) are preferablyhydroxybutylvinyl ether, diethyleneglycolvinyl ether, vinyloxobutylenepolyethylene glycol, (with a hydroxy or alkyl terminus),2-aminoethylvinyl ether, glycidylvinyl ether and butyl- or isobutylvinylether.

Monomers which form the structural unit (IVb) are preferably3-allyloxy-2-hydroxypropane-1-sulfonic acid and salts thereof,3-allyloxy-1,2-propanediol, allylglycidyl ether, allylethyl ether,2-allyloxyethanol and 1,1,1-tris(hydroxymethylpropane)monoallyl ether.

Monomers which form the structural unit (IVc) are preferablybis-acrylamides and bis-acrylic acid esters which are linked together bymeans of alkylidene, phenylene, benzylidene, cyclohexylidene,hydroxyalkylene or oxyalkylene groups.

The fact that the copolymers contain 5 to 93 wt.-% of the structuralunits a), 1 to 50 wt.-% of the structural units b), 5 to 93 wt.-% of thestructural units c) and 1 to 25 wt.-% of the structural units d) wherethe components a) to d) add up to 100 wt.-% is regarded as beingfundamental to the invention.

Preferably used copolymers contain 40 to 83 wt.-% of the structuralunits a), 5 to 48 wt.-% of the structural units b), 5 to 53 wt.-% of thestructural units c) and 1 to 10 wt.-% of the structural units d), wherea), b), c) and d) amount to 100 wt.-%.

The number of repeating structural units in the copolymers according tothe invention is unlimited. However, it has proven to be advantageous toadjust the number of structural units such that the copolymers have amolecular weight of 10,000 to 3,000,000 g/mol and in particular of100,000 to 1,000,000 g/mol.

The copolymers according to the invention can be produced by a number ofpolymerization processes. Bulk, solution and inverse emulsionpolymerization, as well as suspension polymerization in an organiccontinuous phase, precipitation polymerization and gel polymerizationare suitable for their production. It is preferable to polymerize insolution or to use gel polymerization for their synthesis especiallypreferably in water as a solvent.

Hence the invention concerns a process for producing the copolymersaccording to the invention in which monomers of formula (Ia) and/or (lb)

in which

-   R¹=hydrogen or C₁-C₅ alkyl,-   R²=C₁-C₂₀ alkylene, carboxy-C₁-C₂₀-alkylene,    carboamido-C₁-C₂₀-alkylene or phenylene-   M=hydrogen, ammonium or a monovalent, divalent or trivalent metal    cation and-   x=1 to 3, especially in an amount of 5 to 93 wt.-% and of formula    (IIa) and/or (IIb)    in which-   R³ and R⁴=—COO⁻(M^(x+))_(1/x) or are together-   R⁵=COO⁻(M^(x+))_(1/x)-   M=hydrogen, ammonium or a monovalent, divalent or trivalent metal    cation and-   x=1 to 3, especially in an amount of 1 to 50 wt.-%, and    of formula (III)    in which-   R⁶=hydrogen or C₁-C₅ alkyl-   R⁷ and R⁸=hydrogen or C₁-C₁₀ alkyl or are together —(CH₂)_(y)—and-   y=3 to 7, especially in an amount of 5 to 93 wt.-%,    and of formula (IVa) and/or (IVb) and/or (IVc), especially in an    amount of 1 to 25 wt.-%:    in which-   R⁹=hydrogen or C₁-C₅ alkyl-   R¹⁰=C₁-C₁₀ alkyl, C₁-C₁₀ aminoalkyl, C₁-C₂₀ hydroxyalkyl, C₁-C₄    alkyl or hydroxyl-terminated mono- or poly-C₂-C₃-alkyleneoxy    (containing 1 to 400 alkyleneoxy units), C₇-C₂₀ alkylaryl, C₇-C₂₀    hydroxyalkylaryl, C₆-C₁₀ aryl, C₆-C₁₀ hydroxyaryl-   R¹¹, R¹² and R¹³=hydrogen or C₁-C₅ alkyl and-   R¹⁴: hydrogen, C₁-C₂₀ alkyl, C₁-C₁₀ aminoalkyl, C₁-C₂₀ hydroxyalkyl,    C₁-C₄ alkyl or hydroxyl-terminated mono- or poly-C₂-C₃-alkyleneoxy    (containing 1 to 400 alkyleneoxy units), C₇-C₂₀ alkylaryl, C₇-C₂₀    hydroxyalkylaryl, C₆-C₁₀ aryl, C₆-C₁₀ hydroxyaryl or C₁-C₂₀    alkylenesulfonic acids optionally substituted with hydroxyl    group(s), and ammonium, alkali or earth alkaline earth salts thereof-   R=H, CH₃-   X=O, NH-   n=1 to 6-   r, s=0 to 5-   t=1 or 2-   u=1 to 50 and-   R⁶ has the above-mentioned meaning,    are polymerized in bulk or in solution at temperatures of −5 to 120°    C.

For the inverse emulsion polymerization of the copolymers according tothe invention, the monomers are dissolved in the aqueous phase andemulsified with the aid of a protective colloid in a standard organicsolvent such as cyclohexane, toluene, heptane, petroleum ether ormineral oils and started with the aid of a commercial initiator that issoluble in organic solvents such as dibenzoyl peroxide orazoisobutyronitrile.

Suspension polymerization in an organic continuous phase differs fromthe inverse emulsion polymerization with respect to the selectedinitiator where a water-soluble initiator system is used. The polymerparticles that are obtained in this process are often larger than ininverse emulsion polymerization.

If the copolymers according to the invention are synthesized by aprecipitation polymerization process, then water-soluble C₁-C₅ alkanolssuch as methanol, ethanol or tert.-butanol are particularly suitable assolvents. Especially the latter is preferred due to its lowchain-transfer constant if it is intended to produce polymers having alarge molecular weight. During the precipitation polymerization thepolymer precipitates as a powder and can be isolated by simplefiltration.

If it is intended to achieve high molecular weights, gel polymerizationis particularly well suited. In this process the monomer is dissolved ina solvent and the monomer content of the aqueous solution is usually 25to 75 wt.-%. Polymerization results in a high-molecular weight gel whichcan subsequently be reduced to small pieces and dried.

All polymerizations are started in a temperature range of −5 to 120° C.A start temperature between 5 and 90° C. is preferred. The reactions canbe carried out under normal pressure or elevated pressure. Initiationand polymerization in an atmosphere of protective gas is advantageous insome cases.

The polymerization can be initiated in various ways. It can be startedthermally by suitable initiators in which case azo compounds arepreferably used. Initiation by initiators suitable for photochemicaldegradation is also possible. α-Substituted carbonyl compounds such asbenzoin or benzil derivatives are preferably used. A photo-sensitizercan optionally be added to these light-sensitive initiators.

Many polymerization processes for producing the copolymers according tothe invention result in high molecular weights. Lower molecular weightsare obtained by adding substances with large chain-transfer constants tothe reaction solution. Multi-functional amines such as tetraethylenepentamine, alcohols such as methanol, ethanol or isopropanol andmercaptans such as mercaptoethanol are preferred in this case. The useof allyl ethers as comonomers also results in products withcomparatively low molecular weights.

Depending on the process used, the polymerizations can proceed withvarious degrees of exothermy. The heat generated at the start ofpolymerization can be reduced by adding suitable moderators in whichcase alkylamines are preferably used for this.

The polymer compounds according to the invention are excellentlysuitable as water retention agents, thickeners or anti-segregationagents for aqueous building material systems containing mineral bindingagents such as cement, lime, gypsum and anhydrite etc. or for claysuspensions preferably based on bentonite.

The copolymers according to the invention are preferably and usuallyused in amounts between 0.05 and 5% by weight based on the dry weight ofthe building material system.

The copolymers according to the invention have excellent waterretention, thickening and anti-segregation properties without prolongingthe setting and stiffening properties.

The following examples are intended to further elucidate the invention.

EXAMPLES Production Examples Example 1

11.9 g calcium hydroxide was suspended in 200 g tap water, 61.3 g AMPSand 3.2 g maleic anhydride were added and the pH was adjusted to 8 withadditional calcium hydroxide. 7 g N-vinylpyrrolidone and 1.6 g3-allyloxy-2,3-epoxypropane were subsequently added, the reactionsolution was flushed with nitrogen and heated to 50° C. After adding 0.3g 2,2′-azobis(N,N′-dimethyleneisobutyramidine)dihydrochloride, thereaction was stirred for 3 hours at 50° C.

Example 2

11.9 g calcium hydroxide was suspended in 200 g tap water, 61.3 g AMPSand 1.6 g maleic anhydride were added and the pH was adjusted to 6 withadditional calcium hydroxide. 8.6 g N-vinylcaprolactam was subsequentlyadded, the reaction solution was flushed with nitrogen and heated to 50°C. After adding 4,4 g vinyloxy-butylene polyethylene glycol (MW ca. 500g/mol) and 0.3 g 2,2′-azobis(2-amidinopropane)dihydrochloride, thereaction was stirred for 3 hours at 50° C.

Example 3 (Gel Polymerization)

14.34 g sodium hydroxide was suspended in 200 g tap water, 61.3 g AMPSand 2.9 g maleic anhydride were added and the pH was adjusted to 8 withadditional sodium hydroxide. 15 g N-vinylacetamide and 21.3 gN-vinylformamide were subsequently added, the reaction solution wasflushed with nitrogen and heated to 55° C. After adding 4.6 g of a 40%solution of 3-allyl-2-hydroxypropanesulfonic acid, sodium salt and 0.3 g2,2′-azobis(2-amidinopropane)dihydrochloride, the reaction was allowedto stand for 3 hours at 55° C.

Example 4

64 g calcium hydroxide was suspended in 800 g tap water, 245 g AMPS and23 g maleic anhydride were added and the pH was adjusted to 8 withadditional calcium hydroxide. 34 g N-vinylcaprolactam was subsequentlyadded, the reaction solution was flushed with nitrogen and heated to 60°C. After adding 6 g hydroxybutylvinyl ether and 1.2 g2,2′-azobis(2-amidinopropane)dihydrochloride, the reaction was stirredfor 3 hours at 60° C.

Example 5

11.6 g calcium hydroxide was suspended in 200 g tap water, 61.3 g AMPSand 1.2 g maleic anhydride were added and the pH was adjusted to 8 withadditional calcium hydroxide. 25.8 g N-vinylcaprolactam and 1.4 gmethylene bisacrylamide were subsequently added, the reaction solutionwas flushed with nitrogen and heated to 62° C. After adding 0.6 gtetraethylene pentamine and 0.85 g sodium persulfate, the reaction wasstirred for 3 hours at 60° C.

Examples of Application

The copolymers according to the invention were examined with regard totheir suitability as anti-segregation agents, thickeners and waterretention agents for plaster pastes, cement slurries and claysuspensions.

Example 6

The effect of the polymers according to the invention asanti-segregation agents for cement slurries was determined according toDIN EN 480-4. For this 1500 g cement CEM I 42.5 R was mixed with 900 gtap water and 7.5 g polymer, 900 ml was filled into a measuringcylinder, the bleed water was withdrawn after certain times and its massin g was determined. The following accumulated values were obtained(table 1): TABLE 1 Bleed water values for CEM I 42.5 R cement (w/c =0.6; 0.5 wt-% polymer relative to cement) Bleed water (g) after Polymer10 min 60 min 120 min — 3.9 75.1 134.4 1 0.1 0.2 0.2 2 0.2 0.2 0.2 3 0.20.2 0.2 4 0.7 0.8 0.8

Example 7

The polymers according to the invention are also suitable as waterretention agents for cement slurries. The water retention capacity ofthe cement slurries treated with the polymers according to the inventionwas determined according to DIN 18 555. 350 g CEM I 42.5 R cement wasmixed with 210 g tap water and 2.5 g polymer and homogenized. Theresults obtained are shown in table 2. TABLE 2 Water retention capacityof the described polymers according to the invention in CEM I 42.5 Rcement slurries water retention capacity Polymer (%) — 64.8 1 98.2 298.4 3 99.0 4 97.8 5 89.5

Example 8

The thickening action of the polymers according to the invention oncement slurries was determined with the aid of the flow index. Acommercial methyl cellulose was selected as the reference. 0.75 gpolymer was dissolved in 180 g tap water and 300 g cement CEM I 42.5 Rwas subsequently added. The slurries were allowed to stand for 60 secand afterwards stirred vigorously for 120 sec. The slurries were pouredinto a Vicat ring (H=40 mm, d_(small)=65 mm, d_(large)=75 mm) standingon a glass plate to the level of the rim. The Vicat ring was lifted 2 cmand held for about 5 sec above the slurries that flowed out. Thediameter of the slurries that had flown out was measured in two axeswhich were perpendicular to one another. The measurement was repeatedonce. The arithmetic mean of all four measurements gives the flow index.The values obtained are shown in table 3. TABLE 3 Flow index of the CEMI 42.5 R cement slurries treated with the polymers according to theinvention Flow index Polymer cm — 26.0 methyl cellulose 22.0 (reference)1 19.5 2 21.5 3 20.0 5 23.0

Example 9

The polymers according to the invention are suitable as water retentionagents for plaster pastes. The water retention capacity of the plasterpastes treated with the polymers according to the invention wasdetermined according to DIN 18 555. 350 g β-hemihydrate was mixed with210 g tap water, 0.25 g Retardan®P (retarding agent for plasters fromthe Tricosal Company, Illertissen) and 2.5 g polymer and homogenized.The results obtained were compared with those for a commercial methylcellulose. Results of the measurements are shown in table 4. TABLE 4Water retention capacity of the described polymers according to theinvention in plaster pastes Water retention capacity Polymer (%) — 73.2methyl cellulose 98.7 (reference) 1 95.2 2 95.1 3 98.2

Example 10

The thickening action of the polymers according to the invention inplaster paste was determined with the aid of a FANN rotationviscosimeter (r_(rotor)=1.8415 cm, r_(stator)=1.7245 cm,h_(stator)=3.800 cm, d_(ring gap)=0.1170 cm, instrument constant K=300.0(spring F1)). A commercial methyl cellulose was chosen as a reference.0.25 g Retardan®P (retarding agent for plasters from the TricosalCompany, Illertissen) and 0.75 g polymer were dissolved in 245 g tapwater and subsequently 350 g β-semi-hydrate was stirred in. Theviscosity of the plaster paste was subsequently measured at a sheargradient y of 10.2 s⁻¹. The values obtained are shown in table 5. TABLE5 Vicosities of the polymers according to the invention in plaster pasteShear stress at Viscosity at y = 10.2 s⁻¹ y = 10.2 s⁻¹ Polymer Pa mPas —6.1 350 methyl cellulose 7.6 440 (reference) 1 11.2 650 2 15.8 910 3 8.2470

Example 11

The thickening action of the polymers according to the invention on claysuspensions was determined with the aid of a FANN rotation viscosimeter(r_(rotor)=1.8415 cm, r_(stator)=1.7245 cm, h_(stator)=3.800 cm,d_(ring gap)=0.1170 cm, instrument constant K=300.0 (spring F1)). Forthis 10.0 g bentonite was suspended in 350 ml tap water and 0.75 gpolymer was subsequently added. The vicosity of the bentonite suspensionwas subsequently measured at a shear gradient of 10.2 s⁻¹. The valuesobtained are shown in table 6. TABLE 6 Shear stress at y = 10.2 s⁻¹Viscosity at Polymer Pa mPas — 0.5 29 1 1.0 60 2 1.0 60 3 1.5 90

Example 12

The start and end of setting was determined according to Vicat (DIN EN196-3). For this 500 g cement CEM 142.5 R was mixed with 210 g tap waterand 2.5 g polymer. The mixture was homogenized and the cement slurrieswere subsequently measured. A commercial methyl cellulose was measuredas a reference. The measured setting times are shown in table 7. TABLE 7Start and end of setting determined according to DIN EN 196-3 of thecement slurries treated with the polymers according to the inventionStart of setting End of setting Polymer (h:min) (h:min) — 4:00 5:30methyl cellulose 7:00 8:45 (reference) 1 3:15 4:45 2 4:00 5:00 3 4:455:45 4 4:15 5:45

1. Water-soluble copolymers based on olefinic sulfonic acids,characterized in that they contain a) 5 to 93 wt.-% structural units offormula (Ia) and/or (Ib)

in which R¹=hydrogen or C₁-C₅ alkyl, R²=C₁-C₂₀ alkylene,carboxy-C₁-C₂₀-alkylene, carboamido-C₁-C₂₀-alkylene or phenyleneM=hydrogen, ammonium or a monovalent, divalent or trivalent metal cationand x=1 to 3 b) 1 to 50 wt.-% structural units of formula (IIa) and/or(IIb)

in which R³ and R⁴=—COO⁻(M^(x+))_(1/x) or are together

R⁵=—CoO⁻(M^(x+))_(1/x), M=hydrogen, ammonium or a monovalent, divalentor trivalent metal cation and x=1 to 3 c) 5 to 93 wt-% structural unitsof formula (III)

in which R⁶=hydrogen or C₁-C₅ alkyl R⁷ and R⁸=hydrogen or C₁-C₁₀ alkylor are together —(CH₂)_(y)— and y=3 to 7 d) 1 to 25 wt.-% structuralunits of formula (IVa) and/or (IVb) and/or (IVc)

in which R⁹ hydrogen or C₁-C₅ alkyl R¹⁰=C₁-C₁₀ alkyl, C₁-C₁₀ aminoalkyl,C₁-C₂₀ hydroxyalkyl, C₁-C₄ alkyl or hydroxyl-terminated mono- orpoly-C₂-C₃-alkyleneoxy (containing 1 to 400 alkyleneoxy units), C₇-C₂₀alkylaryl, C₇-C₂₀ hydroxyalkylaryl, C₆-C₁₀ aryl, C₆-C₁₀ hydroxyaryl R¹¹,R¹² and R¹³=hydrogen or C₁-C₅ alkyl, and R¹⁴=hydrogen, C₁-C₂₀ alkyl,C₁-C₁₀ aminoalkyl, C₁-C₂₀ hydroxyalkyl, C₁-C₄ alkyl orhydroxyl-terminated mono- or poly-C₂-C₃-alkyleneoxy (containing 1 to 400alkyleneoxy units), C₇-C₂₀ alkylaryl, C₇-C₂₀ hydroxyalkylaryl, C₆-C₁₀aryl, C₆-C₁₀ hydroxyaryl or C₁-C₂₀ alkylenesulfonic acids optionallysubstituted with hydroxyl group(s) and ammonium, alkali or alkalineearth salts thereof

R¹⁶=H, CH₃ X=O, NH n=1 to 6 r, s=0 to 5 t=1 or 2 u=1 to 50 and R⁶ hasthe above-mentioned meaning and that the components a) to d) add up to100 wt.-%.
 2. Copolymers as claimed in claim 1, characterized in thatR¹=hydrogen and R²=—CO—NH—C(CH₃)₂—CH₂— in formula (Ia).
 3. Copolymers asclaimed in claim 1, wherein in formulae (Ia), (Ib), (IIa) and (IIIb) themonovalent metal cations denote alkali ions and in particular sodium andpotassium ions, the divalent metal cations denote alkaline earth ionsand in particular calcium and magnesium ions and the trivalent metalcations denote aluminum or iron ions.
 4. Copolymers as claimed in claim1, wherein y=3 to 5 in formula (III).
 5. Copolymers as claimed in claim1, wherein in formulae (IVa) and/or (IVb) the C₁-C₂₀ hydroxyalkyl,C₇-C₂₀ hydroxy-alkylaryl, C₆-C₁₀ hydroxylaryl residues for R¹⁰ and R¹⁴have one or more hydroxyl groups.
 6. Copolymers as claimed in claim 1,wherein, in formula (IVa) R⁹ denotes hydrogen and R¹⁰ denotes a C₁-C₆hydroxyalkyl or a methyl-terminated or hydroxyl-terminated mono- orpoly-C₂-C₃-alkyleneoxy residue.
 7. Copolymers as claimed in claim 1,wherein, in formula (IVb), R¹¹, R¹² and R¹³ denote hydrogen and R¹⁴denotes 2,3-dihydroxypropyl, 3-hydroxypropyl or2-hydroxypropyl-3-sulfonic acid as well as ammonium, alkali and alkalineearth salts thereof.
 8. Copolymers as claimed in claim 1, comprising 40to 83 wt.-% structural units a), 5 to 48 wt.-% structural units b), 5 to53 wt.-% structural units c) and 1 to 10 wt.-% structural units d). 9.Copolymers as claimed in claim 1, they have having a molecular weight of10,000 to 3,000,000 g/mol.
 10. Copolymers as claimed in claim 9,characterized in that the molecular weight is between 100,000 g/mol and1,000,000 g/mol.
 11. Process for producing the copolymers as claimed inclaim 1, wherein monomers of formula (Ia) and/or (Ib)

in which R¹=hydrogen or C₁-C₅ alkyl, R²=C₁-C₂₀ alkylene,carboxy-C₁-C₂₀-alkylene, carboamido-C₁-C₂₀-alkylene or phenyleneM=hydrogen, ammonium or a monovalent, divalent or trivalent metal cationand x=1 to 3, and of formula (IIa) and/or (IIb)

in which R³ and R⁴=—COO⁻(M^(x+))_(1/x) or are together

R⁵=—COO⁻(M^(x+))_(1/x) M=hydrogen, ammonium or a monovalent, divalent ortrivalent metal cation and x=1 to 3, and of formula (III)

in which R⁶=hydrogen or C₁-C₅ alkyl R⁷ and R⁸=hydrogen or C₁-C₁₀ alkylor are together —(CH₂)_(y)—and y=3 to 7, and of formula (IVa) and/or(IVb) and/or (IVc),

in which R⁹=hydrogen or C₁-C₅ alkyl R¹⁰=C₁-C₁₀ alkyl, C₁-C₁₀ aminoalkyl,C₁-C₂₀ hydroxyalkyl, C₁-C₄ alkyl or hydroxyl-terminated mono- orpoly-C₂-C₃-alkyleneoxy (containing 1 to 400 alkyleneoxy units), C₇-C₂₀alkylaryl, C₇-C₂₀ hydroxyalkylaryl, C₆-C₁₀ aryl, C₆-C₁₀ hydroxyaryl R¹¹,R¹² and R¹³=hydrogen or C₁-C₅ alkyl and R¹⁴=hydrogen, C₁-C₂₀ alkyl,C₁-C₁₀ aminoalkyl, C₁-C₂₀ hydroxyalkyl, C₁-C₄ alkyl orhydroxyl-terminated mono- or poly-C₂-C₃-alkyleneoxy (containing 1 to 400alkyleneoxy units), C₇-C₂₀ alkylaryl, C₇-C₂₀ hydroxyalkylaryl, C₆-C₁₀aryl, C₆-C₁₀ hydroxyaryl or C₁-C₂₀ alkylenesulfonic acids optionallysubstituted with hydroxyl group(s) and ammonium, alkali or alkalineearth salts thereof

R¹⁶=H, CH₃ X=O, NH n=1 to 6 r, s=0 to 5 t=1 or 2 u=1 to 50 and R⁶ hasthe above-mentioned meaning, are polymerized in bulk or in solution attemperatures of −5 to 120° C.
 12. Process as claimed in claim 11,characterized in that an inverse emulsion polymerization is carried outin an organic solvent selected from the group comprising cyclohexane,toluene, heptane, benzene, petroleum ether or mineral oils in thepresence of a protective colloid.
 13. Process as claimed in claim 11,characterized in that a suspension polymerization is carried out in acontinuous organic phase with the aid of a water-soluble initiatorsystem.
 14. Process as claimed in claim 11, characterized in that aprecipitation polymerization is carried out using a water-soluble C₁-C₅alcanol as a solvent.
 15. Process as claimed in claim 11, wherein a gelpolymerization is carried out in which the amount of monomer in anaqueous solution is 25 to 75% by weight.
 16. (canceled)
 17. (canceled)18. Water retention agents for aqueous building material systemscontaining mineral binders, or for clay suspensions, comprisingcopolymers of claim
 1. 19. The water retention agents of claim 18,comprising copolymers in an amount of 0.05 to 5% by weight based on thedry weight of the building material system.
 20. Anti-segregation agentsfor aqueous building material systems containing mineral binders, or forclay suspensions, comprising copolymers of claim
 1. 21. Theanti-segregation agents of claim 20, comprising copolymers in an amountof 0.05 to 5% by weight based on the dry weight of the building materialsystem.
 22. A thickener for aqueous building material systems containingmineral binders, or for clay suspensions, comprising copolymers ofclaim
 1. 23. The thickener of claim 22, comprising copolymers in anamount of 0.05 to 5% by weight based on the dry weight of the buildingmaterial system.